arXiv Machine Learning

An Explicit Feedback Contract for Iterative ML-Agent Harnesses

The paper introduces an explicit feedback contract for iterative machine‑learning agents, limiting when agents can observe validation scores and when they may stop iterating. The contract only releases a score once it exceeds a noise threshold derived from the standard error, preventing adaptive over‑selection of the validation split. Experiments on click‑through‑rate prediction, learning‑to‑rank, and a zero‑signal control task show that the contract reduces the validation‑test gap, yields slightly higher test performance, and forces agents to stop earlier—using only 4–12 submissions instead of the full 30 budget used with exact feedback.

arXiv AI
Oct 15

LoopArena: Benchmarking Models as Runtime Controllers for Loop Engineering

LoopArena is a benchmark that evaluates how effectively a model (the Controller) can guide a separate coding agent (the Worker) through long-running tasks by monitoring progress, assigning work, and deciding when to stop. It consists of three settings: Type I with 160 low‑cost control questions, Type II with 80 task slices, and Type III with 80 full tasks. In full tasks, the best observed strict success rate is 36.25%, and Controllers can reduce inference cost by an average of 60.6% while maintaining a strong correlation in performance ranking.

By Yi Wang, Haopeng Zhang, Chengxiang Huang, Rui Dai, Kaikui Liu, Piotr Koniusz, Xiangxiang Chu
arXiv AI
3d ago

When Can You Trust an Agent's Own Verifier? Stress-Testing Counterfactual Rationale Verification Under Search Pressure and Oracle Access

The paper investigates whether an agent’s own verifier remains reliable when the agent is optimized against it. It introduces a stress‑testing framework that measures the pressure ratio ρ, the influence of the verifier on the agent’s search, and four falsifiable probes targeting common failure modes. Applying this framework to the Rationale Consistency Score (RCS) in an LLM agent that designs machine‑learning pipelines, the authors find that the verifier’s impact is minimal in their baseline setup, that agents can shorten claim lists without affecting search, and that pre‑commit probing can hide declines in faithfulness. The study concludes with a proposed reporting standard to audit verifiers before trusting them.

By Jonghyun Lee, Moonsu Kim, Sunghwan Park
arXiv AI
6d ago

JevAgentHarness: Benchmarking, Deploying and Training Decision Models That Share Control with LLMs

JevAgentHarness is a new framework that benchmarks, deploys, and trains decision models to share control with large language models (LLMs) in agentic tasks. It introduces AgentDecisionBench to evaluate decision models from isolated questions to full agent control, revealing that accurate isolated decisions still miss many tasks and that naïve delegation can reduce success. By fitting confidence thresholds per choice and training a 4B decision model on states after agent mistakes, JevAgentHarness achieves high task success while cutting cost and speeding up execution, with results and resources made publicly available.

By Kunlun Zhu, Tao Feng, Xu Han, Heng Wang, Ling Yang, Xiangru Tang, Jiaxuan You, Heng Ji
arXiv AI
Aug 26

CAFE: Self-Improving Search Agents Need Co-Evolving Feedback

CAFE (Coupled Agent–Feedback Evolution) is a framework that lets a shared‑parameter model alternate between acting as a search agent and as a critic that provides corrective feedback. By learning when to request feedback and how to use it, CAFE trains the agent to recover from its own failures and shapes rewards both online and offline. Experiments on seven search benchmarks show that CAFE outperforms other RL‑based agents, maintains gains on out‑of‑domain tests, and reduces hallucinations, indicating that co‑evolving feedback is essential for self‑improving search agents.

By Boyang Liu, Senjie Jin, Peixin Wang, Zhangyue Yin, Yibo Wang, Yuhao Zhou, Xinbing Liang, Shizheng Zhu, Yuhui Wang, Jingqi Tong, Zhiheng Xi, Jiazheng Zhang, Clive Bai, Clarenceai, Blaze Chen, Tao Gui, Qi Zhang, Xuanjing Huang
arXiv AI
Aug 20

SkillGate: Training In-Policy Skill Selection in Long-Horizon Agents

SkillGate is a method that trains agents to select the correct skill from a large slate during an episode by separating credit signals for skill selection and execution. It addresses the problem of selector credit starvation, where traditional outcome-rewarded RL fails to give sufficient credit to the skill-naming tokens, especially in long-horizon tasks. Experiments on five benchmarks show that SkillGate improves a 9B policy’s success rate from 40.8% to 53.2%, reduces exposure to misleading candidates, and requires fewer skill reads.

By Qingyao Li, Wenxiang Jiao, Shuai Shao, Kangning Zhang, Yuan Lu, Yi Guo, Weiwen Liu, Weinan Zhang, Yong Yu
arXiv Computation and Language
Oct 9

Opera: A Verbal Critic Framework for Long-horizon Coding Agents

Opera is a verbal critic framework designed for long‑horizon coding agents, treating each correction as a persistent note that is followed until the problem is resolved. It uses periodic and event‑driven triggers to diagnose issues, audits feedback against visible evidence, and tracks subsequent actions to distinguish compliance from true resolution. In tests, Opera improves the resolve rate of non‑critic agents by up to 12.4, 15.0, and 8.9 percentage points on three benchmarks and provides on‑policy training data that boosts a model’s performance without requiring a critic at inference time.

By Kai Mei, Zhiyuan Hu, Yutong Dai, Juntao Tan, Yifan Zhang, Dingjie Song, Dimitris N. Metaxas, Silvio Savarese, Ran Xu, Zeyuan Chen